A burn-in test means a method for preliminarily reducing initial imperfection by applying a load of a temperature and a voltage to a semiconductor device, and is one of the most effective tests in detecting the initial imperfection among screening tests. A semiconductor wafer is ordinarily loaded from an automatic prober device, and a contact probe is contacted with a gate pad and an emitter pad of all chips by a probe card to conduct the test under an environment of applying a voltage at high temperature. However, a voltage application time for screening the semiconductor wafer reaches a level as much as several hours to several tens of hours, and therefore it has been recognized as a problem to require a great deal of time in testing a plurality of semiconductor wafers.
As a measure for shortening the time in the burn-in test, the burn-in test by applying the voltage and a characteristic inspection test are simultaneously conducted (for example, Japanese Patent Application Laid-Open No. 2017-041495). Moreover, the burn-in test is conducted by arranging a plurality of wafers in conducting a test at high temperature (for example, Japanese Patent Application Laid-Open No. 2008-267818).